Well, I'll tell you what happened, and why it wasn't a flyby.
I had been following this really nice blue LX hatch. 2.25" exhaust, 10-holes, but still very sharp-looking. There appeared to be 3-4 youths inside.
Unfortunately, I was too busy scanning for possible trouble, so when he pulled up to a light (where the road widens), I didn't get to it before it changed. Rather than "jump" the light, I hung a little less than two lenghts behind him. He was definitely lining up, and I blew it. I felt that by hanging back, whatever advantage I had by jumping on it first was negated by the lead he had.
If that's unfair, then I owe that young man an apology.